Pressure measurement devices based on pressure-/voltage converter in chip technology are known for example because of a compressive force sensor by the company Sensortechnics GmbH, Boschstraβe 10, 82178 Puchheim under the device label RFU-E-11710.
The measurement of forces and pressures is necessary in different areas of technology.
A special area, for which the invention is preferably designed, is medical technology, and in that context the measurement of the pressure that arises on the skin of a patient during the application of a bandage that is applied, for example, during lymphatic therapy.
During lymphatic therapy on one leg of a patient one pressure bandage is applied that has to be wrapped in such a manner that the pressure decreases from the foot end in the direction toward the knee or upper thigh. The same applies for pressure bandages on the arm. The medical personnel that apply such bandages are trained for this purpose on models, wherein the respective pressure is measured at different locations.
For that purpose until now pneumatic pressure transducers with balloon-like plastic bags were utilized, attached to which was, for the purpose of the pressure measurement, a connecting hose to a baric measuring device. Besides the fact that such balloon-like plastic bags and connecting hoses leading to a baric measuring device are unwieldy because of their construction size, the measurement accuracy is also, because of different fill volumes of the plastic bags that are filled with air, less than desirable.
It is therefore attractive to utilize more modern pressure/voltage converters in chip technology that today deliver very accurate and simple to evaluate electrical signals while featuring a very small size (for example foot print <10 mm2 and height <4 mm)
One problem is however that such pressure-/voltage converters in chip technology only register forces that act perpendicularly to a sensor area, which for many application areas is not sufficient, for example for the measurement requirements in the context of the lymph drainage described above. The textile bandages feature, in the context of the lymph drainage, in the tensioned state hole-like depressions between the web threads so that the very small sensor measurement surface, which is spherical segment-shaped, can be located in such a depression and would therefore detect a falsely-low pressure.
Similar problems also arise in the case of the evaluation of compressive forces with wheel chairs, chairs, car seats, operating beds, and hospital beds, where for example the stress on back, bottom, legs, arms etc. of a person is to be measured, wherein the forces acting on the pressure-/voltage converter are pointed in different directions. The perpendicular components of these forces also are to be measured in a reliable manner.